Update to Chipmunk 5.3.4. Note, however, that not all
functionality available in Chipmunk 5.3.4 is here yet. But
the bug fixes and performance improvements are.

Fix linking bug present since Hipmunk 5.1.0. Thanks, Sönke Hahn.

Correctly destroy the space in the presence of callbacks.

Workaround difficult-to-reproduce bug in Chipmunk where the
number of contact points in an arbiter would get garbage.
When that happens (and the garbage does look like garbage) we
give an empty list of contact points.